Pneumatic cement-applying apparatus



July 25, 1950 R. M. DOULL ETAL 2,516,584

- PNEUMATIC CEMENT-APPLYING APPARATUS Filed De. 11, 1947 INVENTORSROBERT.M.DOULL MAjKO RADONICH ATTORNEYS water iing.

Patented July 25, 1950 cause stars-s PNEUMATIC, pEME'Nir-APPLYINGAPPARATUS Robert M. Doull and Marko Radonich, Montreal, Quebec, CanadaApplication December 11, 11947, ISerialNo. 791,064

2 Claims. 1

This invention relates to pneumatic cementapplying apparatus in whichcompressed air is utilized to shoot a hydrated mixture of sand andcement aggregate through a nozzle onto the surface to be covered. In theconventional apgparatus of this type the aggregate is supplied to thenozzle through a flexible hose and the total amount of water requiredfor hydration is introduced through a water ring located at or near thepoint where the aggregate enters the nozzle. In U. S. Patent 2,392,408,granted Jan, ,8, 1946, there is described an improved pneumaticcement-applying apparatus wherein improved hydration of the aggregateand other advantages are obtained by the provision of a rear water ringthrough which part of the total amount of water required for hydrationis added to the aggregate at a point located an appreciable distance inadvance of the point where the aggregate enters the nozzle, the balanceof the required amount of water being added through a front water ringlocated at or near the point of entry of the aggregate into the nozzle.In "this apparatus the front and rear Water rings are iconnected toseparate branches of a water sup- ';ply pipe. jI hese branches areequipped with 'v ailves which-are adjusted by 'the op'era'tor to pre-;determine the proportion of the required amount of wateradded to theaggregate at each ring.

,The best results are obtained when the valves .are accurately adjustedso that approximately one-third of the total amount of water requiredfor hydration is-added at the rear'water'ring and the balance added tothe aggregate at the front Efiicient operation of the apparatusdescribed in said prior patent requires accurate proportioning of therelative amounts of water supplied to the aggregate through the frontand rear water rings and experience has shown that the adjustmentsnecessary to accomplish this cannot "safely be left to the judgment orguesswork of the operator. Difierent aggregates re quire difierentamounts of water for eflicient hydration and it takes considerable timefor a skilled operator adjustments necessary to ensure for differentconditions of operation, the required accurate proportionatedistribution of the water between the front and the rear water rings.Because of this it sometimes happens that the potential efilciency ofoperation of the apparatus described in our prior patent is not realizedin practice owusing the apparatus described invour prior patent toacquire the skill and judgment necessary to bperate the .water supplyvalves to provide the ing to incorrect setting of the water supplyvalves.

Another undesirable feature of the apparatus disclosedin said priorpatent is the existence of a differential pressure between the front andrear water rings which adversely aiiects the accurate .proportioning'ofthe water between the two rings and also tends to reduce the pressure onthe rear ring with-resulting plugging of the orifice of this ring andsubsequent' losspf time and faulty operation.

With the foregoing in mind one object of the present invention is toprovide an improved pneumatic cement-applying apparatus in which theproportionate distribution of water between the front and rear waterrings is automatically taken [care of in a foolproof manner;

Another object of the invention isfto provide an improved pneumaticcement-applying apparatus in which provision is made for maintainingidentical water pressure conditions on each of the front and rear waterrings.

.Qther objeotsfadva'ntages and'characteristic iteature's of theinvention will bejrnore readily understood Ifrornthe followingdescription of the accdmpanying drawings illustrating what We nowconceive to be the preferred embodiment of our invention. p

In these drawings: i

The single figure is a longitudinal sectional view of a pneumaticcement-applying apparatus embodying our invention. V

Referring more particularly to the drawing, 5 designates -a-nozzlethrough which. :the hydrated sand and cement aggregate is prejected ontothe surface to :beooVQItBd. The rear endoi the nozzle is screwed into:the internally threadedtront end I of a'ringwshaped nozzle couplings. Arubber liners arranged ini'nozzlea andis'provided, at-itsrearend, withan outwardly directed sealing flange it clamped between the rear end of"the-nozzle and the front 'side:ofan annular flange l extending inwardlyfrom an intermediate poi";- tion of coupling 8. 1 The rear end portion12 of coupling ll is "in- ,t'ernallythreaded andscrewed onto-the frontend of'a metal tube is. The rear and of tube 13' is screwed into theinternally threaded iront end portion M of a ring-esha'ped'hosegcoupling-'l5"having an internally threaded rear end p'ortion it in which thedelivery end of a flexible hose I? is secured by an externally threadedfitting l8. Coupling i5 is machined to make a running fit on tube l3 topermit convenient removal of coupling l5 and other interior parts of thecomplete asseiribly hereinafter described. Coupling ii is locked inplace by locknut la.

Couplings 8 and I5 serve, in conjunction with tube 13, to provide theouter and end walls of a water jacket whose inner wall is formed by aninner tube 2! and front and rear water rings 22 and 23. i

The front water ring 22 is machined to provide a front spigot portion 24of reduced diameter which is a press fit in a recess 25 provided in therear side of coupling flange H. The rear portion of water ring 22 issimilarly machined to provide a rear spigot portion 26 which is a pressfit in the front end of tube 21. The rear water ring 23 is similarlymachined to provide a spigot portion 21 which is a press fit in the rearend of tube 2i and a second spigot portion 28 which is a press flt in arecess 29 provided in an annular flange 30 projecting inwardly from anintermediate portion of the hose coupling ring IS.

A tubular rubber liner 3| is cemented to the inside of tube 2! so thatit extends the full distance between the front and rear water rings 22and 23. The inner circumferential surfaces of front and rear water rings22 and 23 are flush with the inner circumferential surface of liner 3!and form therewith a smooth tubular passage 32 through which the sandand cement aggregate is forced from the delivery end of the hose 1! toand through the nozzle 5.

Front water ring 22 is pierced by holes 33 through which water isdelivered from water jacket 20 to the sand and cement aggregate atapproximately the point where the aggregate enters nozzle 5. Rear waterring 23 is provided with similar holes 34 through which water isdelivered from the water jacket to the sand and cement aggregate atpoints located an appreciable distance in advance of the point of entryof the aggregate into nozzle 5.

The number and/or size of the holes 33 and 34 provided in the front andrear water rings 22 and 23 is predetermined so that the water is meteredto give the correct proportionate distribution between the two waterrings. The arrangement and/or size of the holes in the two rings ispreferably predetermined so that approximately onethird of the totalamount of water required for hydration is delivered through the holes 34of rear water ring 23 and the balance through the holes 33 of frontwater ring 22.

The provision of the common water jacket 20 through which the water isdelivered to both water rings ensures the maintenance of identical waterpressure conditions at each ring and is an important factor inmaintaining accurate relative proportioning of the amount of watersupplied to the aggregate through said rings.

The holes 33 and 34 of water rings 22 and23 are preferably inclined, asshown, so that the water flowing through these holes is directed in thedirection of flow of the aggregate through the water rings.

Water under pressure may be supplied to water jacket 20 in any suitablemanner. In the present instance we have shown a water supply hose 36having its delivery end screwed into a water inlet opening 31 providedin the nozzle coupling 8 at the rear side of flange H.

Another advantage of the present invention is that it provides aself-contained hydration unit which is lighter in weight than theequivalent arrangement described in our prior patent and which iscomposed of parts which are accurately machined to ensure tight jointsin the assembled relation thereof and which can be assembled anddisassembled with great ease and rapidity.

Having thus described the nature of our invention and a preferredembodiment thereof, it will be understood that various modifications maybe resorted to within the scope and spirit of the invention as definedby the appended claims.

We claim:

1. In pneumatic cement applying apparatus of the character described, ahydration unit comprising front and rear centrally apertured end memberseach having internally threaded front and rear end portions and aninwardly directed intermediate annular flange, an outer tube having itsfront and rear ends screwed, respectively, into the internally threadedrear end of the front end member and the internally threaded front endof the rear end member, said tube formin with said end members, theouter and end walls of a water jacket, separately formed front and rearwater rings butted, respectively, against the rear side of the flange ofthe front end member and the front side of the flange of the rear endmember so that said rings form end portions of the inner wall of thewater jacket, an inner tube connecting said water rings and forming animperforate intermediate portion of the inner wall of the water jacket,said rings being pierced by openings extending from the outer to theinner circumference thereof and providing water passages through whichwater is discharged from the water jacket into the space surrounded bysaid rings, means for supplying water under pressure to said waterjacket, an aggregate supply conduit screwed into the internally threadedrear end of said rear end member and a nozzle screwed into internallythreaded front end of said front end member.

2. Pneumatic cement applying apparatus as set forth in claim 1, in whichthe water rings are provided with end portions of reduced externaldiameter fitted in the ends'of said inner tube and opposite end portionsof reduced external diameter fitted in recesses provided in the flangesof said end members and in which the inner portion of the inner tubelying between said water rings is covered by a resilient non-metallictubular liner having its inner annular surface flush with the innerannular surfaces of said water rings.

RQBERT M. DOULL.

MARKO RADONICH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

